Multi-speed hybrid transmission and transmission operating method

ABSTRACT

A hybrid transmission system with a multi-speed gearbox. The multi-speed gearbox is configured to rotationally couple a prime mover and an electric machine to different gear ratios during a hybrid drive mode. The multi-speed gearbox includes an electric drive interface gear positioned coaxial to a first primary shaft and a second primary shaft and idly mounted, free to spin, to the second primary shaft and an output shaft that includes an output shaft gear which is fixedly coupled thereto meshes with a gear on a secondary shaft.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to U.S. Provisional PatentApplication No. 63/265,618, entitled “MULTI-SPEED HYBRID TRANSMISSIONAND TRANSMISSION OPERATING METHOD”, and filed Dec. 17, 2021. The entirecontents of the above-listed application are hereby incorporated byreference for all purposes.

TECHNICAL FIELD

The present description relates generally to a vehicle transmission anda method for operation of the transmission.

BACKGROUND & SUMMARY

Some powertrains in hybrid and other vehicle types have multi-faceteddemands in relation to powertrain functionality and performance.However, previous transmission systems have exhibited issues with regardto modularity and cross-powertrain platform flexibility. For instance,the inventor has recognized that certain previous transmissions inhybrid and all electric vehicles as well as internal combustion engine(ICE) vehicles have demonstrated an inability to share common componentlayouts which creates design rigidity and hinders cross-platformdevelopment, in some instances. This design rigidity may increase theduration of transmission development and manufacturing. For example,transmissions with single and dual-clutch layouts may have incompatiblearchitectures, especially in hybrid vehicles, which may lead to separatedevelopment and manufacturing processes, in some cases.

EP 1232891 B1 to Jouve et al., for example, discloses an automatictransmission in a hybrid vehicle. In Jouve's automatic transmissionmechanical power is transferred to a primary shaft from both an engineand an electric motor at opposing ends of the shaft.

U.S. Pat. No. 9,618,085 B2 to Dzafic et al. discloses a seven speeddual-clutch transmission with a three axis layout where a geartrain forthe motor has two axes to arrive at the primary shaft as well as anelectric motor axis.

The inventor has recognized several drawbacks with Jouve's transmissionas well as Dzafic's transmission. For instance, the use of a three axislayout and the accompanying housing in Dzafic's transmission, maypresent difficulties with regard to adapting the dual-clutchtransmission for use in other vehicle platforms, such as automatedmanual transmissions (AMTs) or manual transmissions (MTs) that have asingle clutch layout. On the other hand, Jouve's transmission maypresent challenges with regard to adapting the transmission for vehicleplatforms with dual-clutch layouts. For instance, driving the primaryshaft at opposing ends with an engine and electric motor may posebarriers to adapting the system for use in a dual-clutch transmission.The inventor has therefore recognized a desire to efficiently adapt atransmission for both single and dual-clutch arrangements. Further, theinventor has also recognized a desire to use a common transmissionplatform in both hybrid powertrains as well as internal combustionengine (ICE) powertrains. The inventor has even further recognized adesire to increase transmission efficiency and vehicle range while alsodelivering a higher transmittable torque by decreasing the lengthbetween the bearing supports. Still further the inventor has recognizeda desire to expand the number of gear combinations that can be driven bythe electric machine in a hybrid drive mode.

The inventor has developed a hybrid transmission system to at leastpartially overcome the aforementioned challenges and achieve theaforementioned design goals. In one example, the hybrid transmissionsystem includes a multi-speed gearbox. The multi-speed gearbox isconfigured to rotationally couple a prime mover (e.g., an internalcombustion engine, a hydrogen internal combustion engine, and the like)and an electric machine to different gear ratios during a hybrid drivemode. Further the multi-speed gearbox includes an electric driveinterface gear positioned coaxial to a first primary shaft and a secondprimary shaft. Further, the electric drive interface gear is idlymounted, free to spin to the second primary shaft, configured to beselectively connected to the second primary shaft and/or a secondaryshaft. The multispeed gearbox further includes an output shaft thatincludes an output shaft gear which is fixedly coupled thereto mesheswith a gear on a secondary shaft. Further in such an example, theelectric drive interface gear is axially positioned between two gearsthat are coaxial to the first primary shaft. When the electric machineand the prime mover are capable of driving separate gears in thegearbox, the system's performance as well as adaptability may beincreased, if desired. Further, the use of the electric drive interfacegear in the gearbox allows the transmission system to be efficientlyoperated in a variety of different modes. The system's operating modesmay include an ICE drive mode, a hybrid drive mode, an electric vehicle(EV) drive mode, an engine cranking mode, a kinetic energy recoverymode, and/or and energy storage device charging mode, for instance.Additionally, the use of the electric drive interface gear furtherenables the system's performance to be further increased due to thelocation of the gear and the shorter span between bearings that can beachieved in the gearbox architecture when compared to previoustransmission designs, if wanted. The abovementioned hybrid transmissionsystem further achieves a higher level of modularity and designflexibility when compared to previous transmissions. For instance, thesystem may be efficiently adapted for use in a dual-clutch transmissionas well as an automated manual or manual transmission while retaining asimilar number of operating gears and/or clutch layout, if so desired.

In a further example, the multi-speed gearbox may include an electricdrive clutch that is configured to selectively couple the electric driveinterface gear to the second primary shaft. Further in one example, theprime mover clutch is a dual-clutch assembly that includes a firstclutch mechanism that configured to selective couple the prime mover tothe first primary shaft and a second clutch mechanism that is configuredto selectively couple the prime mover to the second primary shaft. Theelectric drive clutch allows power to be selectively introduced intodifferent gears in the transmission from the electric machine or viceversa. Consequently, the electric machine may provide electric-boostfunctionality, in certain hybrid modes. For instance, mechanical powermay be continuously delivered through the transmission to the drivewheels from the electric machine while the dual-clutch assembly shifts,thereby increasing system performance. Due to the expanded systemfunctionality and increased performance customer appeal is increased.

It should be understood that the summary above is provided to introducein simplified form a selection of concepts that are further described inthe detailed description. It is not meant to identify key or essentialfeatures of the claimed subject matter, the scope of which is defineduniquely by the claims that follow the detailed description.Furthermore, the claimed subject matter is not limited toimplementations that solve any disadvantages noted above or in any partof this disclosure.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 shows a schematic representation of an example of a vehicle witha powertrain that includes a transmission system.

FIGS. 2A-2H show mechanical power paths for different operating gears inthe transmission system, depicted in FIG. 1 .

FIG. 2I shows a chart that denotes the gearing for an internalcombustion engine (ICE) and an electric machine, in the transmissionsystem, depicted in FIG. 1 , for upshifting and downshifting intopreselected gears in a hybrid drive mode as well as the gears availableto the electric machine in an electric vehicle (EV) mode.

FIG. 2J shows an exemplary bearing arrangement in the transmissionsystem, depicted in FIG. 1 .

FIGS. 4A-4E show sequential mechanical power paths in the transmissionsystem, depicted in FIG. 1 , during a shift event.

FIGS. 5A-5B show sequential mechanical power paths in the transmissionsystem, depicted in FIG. 1 , during another shift event.

FIG. 6 shows a mechanical power path in the transmission system,depicted in FIG. 1 , where the ICE and the electric machine are drivinga common gear and the mechanical power from the electric machine travelsthrough a clutch.

FIGS. 7A-7C show mechanical power paths that occur in the transmission,depicted in FIG. 1 , in different ICE cranking modes.

FIGS. 8A-8D show mechanical power paths that occur in the transmission,depicted in FIG. 1 , while the transmission is operating in an electricvehicle (EV) mode.

FIGS. 9A-9B show mechanical power paths that occur in the transmissionsystem, depicted in FIG. 1 , in different energy storage device chargingmodes.

FIGS. 10A-10D show mechanical power paths that occur in the transmissionsystem, depicted in FIG. 1 , in different energy kinetic energy recoverymodes.

FIGS. 3, 11-19, and 27 show other exemplary transmission systemarchitectures.

FIG. 20 shows a detailed cross-sectional view of an example of atransmission system.

FIG. 21 shows an exploded view of an exemplary transmission system.

FIG. 22 shows a perspective view of an exemplary transmission systemwithin a housing.

FIGS. 23-26 show exemplary vehicles with different electric drivemounting positions.

DETAILED DESCRIPTION

The following description relates to transmission systems and operatingmethods in vehicle powertrains that achieve a comparatively high levelof modularity and design flexibility as well as performance in relationto prior transmission systems. The increased performance andadaptability is achieved by designing a multi-speed gearbox with thecapability to use an engine and an electric machine to drive differentgear ratios in a hybrid drive mode. The increased transmission systemadaptability is also achieved, at least in part, through the use of agear that is configured to serve as an interface for an electric driveunit that includes an electric machine. This gear is referred to hereinas an electric drive interface gear. The electric drive interface gearis positioned coaxial to a primary shaft when the transmission is usedin a hybrid vehicle with an automated manual transmission (AMT), amanual transmission (MT), or dual-clutch transmission (DCT). Theelectric drive interface gear also enables greater flexibility withregard to gear combinations that are driven by the electric machine andinternal combustion engine (ICE) in the hybrid drive mode as well as thegears available in an electric vehicle (EV) drive mode and a kineticenergy recovery mode. The system's performance can be consequentlyincreased due to the system's ability to selectively transfer powerbetween the electric machine and multiple gears residing on a secondaryshaft.

In the DCT embodiment, the electric drive interface gear is configuredto selectively couple to an outer primary shaft. Further, an electricdrive clutch may be used to engage and disengage the electric driveinterface gear from the outer primary shaft. In this way, the power flowfrom the electric machine may either move from the electric driveinterface gear to the secondary shaft, bypassing the primary shafts, ormove from the electric drive interface gear to the outer primary shaftdepending on the transmission's operating mode. Forming the electricdrive clutch in this manner enables the transmission to operate in awide number of modes, if wanted. These modes may include a hybrid drivemode where different gears can be driven by the ICE and the electricmachine, an EV mode with multiple selectable gears, an ICE crankingmode, a battery charging mode, as well as a kinetic energy recoverymode. Further, the electric drive clutch allows the battery to becharged and the ICE to be cranked while the vehicle is at standstill andin motion. In this way, the transmission's capabilities are expanded incomparison to previous transmissions. Specifically, in one example, theelectric drive clutch enables the ICE and the electric machine to drivedifferent gear ratios in certain modes. To elaborate, in specific hybridmode configurations, the electric machine may provide electric-boost tothe transmission even while the dual-clutch assembly shifts betweengears driven by the ICE, for instance. Consequently, system performancemay be further increased, if so desired.

In both the AMT and the DCT architectures the number of transmissiongears and the axial location of said gears and shaft support bearingsmay be substantially equivalent, if wanted. In this way, efficiency withregard to transmission system development and manufacturing may beincreased by using similar gear and bearings arrangements in bothtransmission types, if desired. Further, a similar bearing and geararrangement may be used in a full ICE transmission by removing theelectric drive gear and other electric machine gears and slightlymodifying the transmission's housing. Consequently, the transmission'smodularity may be even further increased with relatively minormodifications to the transmission's architecture.

The transmission system's increased modularity can further allow amechanical reverse assembly and a park-lock assembly to be efficientlyincorporated into the transmission, if desired. In the mechanicalreverse embodiment, the assembly may be coupled to the ends of thesecondary and the primary shafts away from the engine. However, in otherembodiments, reverse drive may be accomplished by designing the electricmachine with electric reverse functionality where the machine spins inopposite directions to achieve forward and reverse drive operation.Consequently, transmission efficiency may be increased, when compared tothe mechanical reverse embodiment. Further in the park lock embodiment,the park lock assembly may be configured to selectively inhibit movementof the transmission's output shaft (or pinion shaft) to facilitateefficient incorporation of the park lock assembly into the transmission.In this way, the transmission's capabilities may be further expandedwithout drastically altering the transmission's architecture, if wanted.Additionally, the kinematic layout of the multi-speed transmissiondescribed herein enables the axial length of the electric motor to beincreased without modification to the transmission, if so desired.

FIG. 1 shows a schematic depiction of a vehicle 100 with a powertrain102 that includes a transmission system 104 with a multi-speed gearbox106. The vehicle may take a variety of forms in different embodiments,such as a light, medium, or heavy duty vehicle for use in both on and/oroff road driving environments. Specifically, in one use-case example,the vehicle may be a high performance vehicle such as a hyper car, asports car, or a grand tourer type sports car that is designed forcomparatively high speed, high performance, and also long distancedriving. However, numerous types of vehicles have been envisioned. Thepowertrain 102, and specifically the transmission system 104, isdepicted as a hybrid powertrain where both an electric machine 108(e.g., a traction motor such as a motor generator) and an ICE 110 (e.g.,a spark and/or compression ignition engine, hydrogen internal combustionengine, and the like) or other suitable prime mover are used as motivepower sources. However, as discussed in greater detail herein thepowertrain may be adapted for use in an ICE vehicle, where the electricmachine is omitted or in an all-electric vehicle where the ICE isomitted.

The electric machine 108 may include conventional components such as arotor, a stator, housing, and the like for generating mechanical poweras well as electrical power, during a regeneration mode, in some cases.Specifically, in one example, the electric machine may be a radial fluxmotor-generator which may achieve relatively high operating speeds in acompact package when compared to other types of motors such as axialflux motors. However, in other examples, an axial flux motor-generatormay be used in the transmission system 104 which may however increasethe motor's size and constrain its operating speed range, in some cases.Other types of electric machines for use in the transmission system 104have also been envisioned. Further, the ICE 110 may include conventionalcomponents such as cylinder(s), piston(s), valves, a fuel deliverysystem, an intake system, an exhaust system, and the like.

The electric machine 108 may be electrically coupled to an energystorage device 112 (e.g., a battery, a capacitor, combinations thereof,and the like), via an inverter 114 when the electric machine is analternating current (AC) machine. Thus, the inverter 114 is designed tochange AC to direct current (DC) and vice versa. Arrows 116 denote theelectrical power flow between the electric machine 108, the inverter114, and the energy storage device 112. The inverter 114 may beinstalled on the transmission or on the vehicle side. In some vehicleplatforms, the inverter may be installed on the vehicle side due totemperature and vibration profiles. Further, the energy storage device112 may be mounted in the vehicle.

The transmission system 104 is illustrated as a dual-clutch transmissionthat includes a dual-clutch assembly 118, described in greater detailherein, although automated manual transmissions, manual transmissions,and full ICE transmissions have been envisioned and are described ingreater detail herein. Thus, the dual-clutch assembly may generally bereferred to as an ICE clutch assembly and may include a single clutchmechanism, in other examples. Further, in other examples, thetransmission system 104 may be included in a transaxle which includes anaxle 120, a differential 122, and the transmission system 104incorporated into one unit. In this way, the transmission may be adaptedfor use in a mid-engine vehicle or a front-engine vehicle. However, inother examples, the transmission, axle, and/or differential may bepackaged as separate units.

The transmission system 104 includes the multi-speed gearbox 106designed to shift between different discrete operating gears. In theillustrated embodiment, the multi-speed gearbox has eight operatinggears. However, in other examples, the multi-speed gearbox may have fouror more operating gears or between four and ten operating gears. Stillfurther in other examples, the multi-speed gearbox may have less thanfour operating gears which may however decrease powertrain performance,in some cases.

The multi-speed gearbox 106 may be configured to transfer torque todrive wheels 124 via the differential 122 (e.g., axle differential). Toelaborate, an output shaft 126 (e.g., pinion shaft) with a bevel gear128 (e.g., a bevel pinion) meshing with a bevel gear 130 (e.g., crowngear) linked to the differential case (or carrier) 132 may be used toform the mechanical attachment between the gearbox and the differential,although other suitable types of gears may be used in other examples.However, other suitable types of mechanical attachment may be used tocouple the gearbox geartrain to the differential. Further, a drop gear127 may be fixedly coupled (e.g., through a splined interface, a weldedinterface, other suitable connections, or combinations thereof) to theoutput shaft 126 and meshes with a fifth gear 153, described in greaterdetail herein. The drive wheels 124 may be rotationally coupled to thedifferential via axle shafts 134 and/or other suitable mechanicalcomponents. Rotational axes of the axle shafts 134 may be arrangedperpendicular to the rotational axes of the electric machine 108, theICE 110, the first primary shaft 140, the second primary shaft 142, thesecondary shaft 146, and/or the output shaft 126. Designing thetransmission system in this manner may enable the system to beefficiently packaged in the vehicle and used in a wider variety ofvehicles, in some instances. However, in alternate examples, the axleshafts may be arranged parallel to the electric machine 108, the ICE110, a first primary shaft 140, a second primary shaft 142, a secondaryshaft 146, and/or the output shaft 126.

Further, the differential 122 may be any of an open differential, anelectronic limited slip differential, a mechanical limited slipdifferential, and the like. The use of the limited slip differential mayincrease performance and vehicle dynamics with regard to vehicletraction while increasing the complexity of the differential.Conversely, the use of an open differential may decrease thedifferential's complexity (e.g., likelihood of degradation) whileimpacting traction under certain conditions, in relation to limited slipdifferentials. A rotational axis of the differential may be arrangedperpendicular to the rotational axis of the electric machine 108.However, in other examples, the differential's rotational axis may beparallel to the electric machine's rotational axis.

The ICE 110 may include an output shaft 136 that may be rotationallycoupled to a flywheel 138 or other suitable coupling mechanism such as adual mass flywheel. Further, a shaft 139 may couple the flywheel 138 tothe dual-clutch assembly 118 in the transmission system 104. Thus, theflywheel 138 may serve as an ICE interface. Further, the dual-clutchassembly 118 may selectively rotationally couple the flywheel 138 to afirst primary shaft 140 and a second primary shaft 142. The firstprimary shaft 140 may be an inner shaft and the second primary shaft maybe an outer primary shaft or vice versa that are coaxial. To expound,the second primary shaft 142 may be hollow and disposed concentricallyabout the first primary shaft 140 or vice versa. In alternateembodiments the dual-clutch assembly may be replaced with a singleclutch assembly for use in a manual transmission or an automated manualtransmission, discussed in greater detail herein.

The dual-clutch assembly 118 may include a first clutch mechanism 143and a second clutch mechanism 144, which may be wet or dry frictionclutches. The first clutch mechanism 143 may include plates (e.g.,friction plates and/or separator plates), and in some cases springs,which are engageable to transfer torque from the flywheel 138 to thefirst primary shaft 140. As such, when the first clutch mechanism 143 isengaged, the flywheel 138 transfers torque to the first primary shaft140. Conversely, when the first clutch mechanism 143 is disengaged,mechanical power transfer through the clutch mechanism is inhibited.Similarly, the second clutch mechanism 144 may include plates (e.g.,friction plates and/or separator plates), and in some cases springs,which are engageable to transfer torque from the flywheel 138 to thesecond primary shaft 142. Thus, when the second clutch mechanism isengaged, the flywheel transfers torque to the second primary shaft andwhen the second clutch mechanism is disengaged torque transfer throughthe second clutch mechanism is inhibited. When the transmission systemincludes the dual-clutch assembly it may be referred to as a dual-clutchtransmission system (e.g., a hybrid dual clutch transmission), in oneexample.

The multi-speed gearbox 106 may further include the secondary shaft 146.The secondary shaft 146 may be designed as a one or two-piece shaft.Sets of gears 147, 148, and 149 may reside on the first primary shaft140, the second primary shaft 142, and the secondary shaft 146,respectively. Each of the sets of gears 147, 148, 149 may includemultiple gears therein. The set of gears 147 on the first primary shaft140 mesh with a portion of the gears in the gear set 149 on thesecondary shaft 146. Specifically, the gears 150, 151, 152, 153 thatmesh with the gears on the first primary shaft 140 may be referred to asodd gears and the gears 154, 155, 156, 157 on the secondary shaft 146that mesh with gears on or coaxial to the second primary shaft 142 maybe referred to as even gears. To elaborate, the gear 150 may be a firstgear, the gear 157 may be a second gear, the gear 151 may be a thirdgear, the gear 155 may be a fourth gear, the gear 153 may be a fifthgear, the gear 154 may be a sixth gear, the gear 152 may be a seventhgear, and the gear 156 may be an eighth gear. This numbering of thedriven gears on the secondary shaft (i.e., first gear through eighthgear) denotes the relative sizes of the gears with the first gear havingthe largest diameter gear and the eighth gear having the smallest. Thefirst through eighth gears, on the secondary shaft, mesh with gears 158,159, 160, 161, 179, 162, 163, and 164, respectively. The gears 158, 160,163, and 179 are coaxial to the first primary shaft 140 and the gears159, 161, 162, and 164 are coaxial to the second primary shaft 142.Thus, the first through the eighth gears denote the relative gear ratiosbetween the gear combinations where the first gear has a highernumerical ratio than the second gear and so on. The pair of gears thatare formed via the meshing between gears on the secondary shaft andgears on the primary shafts may be referred to as gear combinations. Assuch, the pair of gears 150 and 158 may be referred to as a first gearcombination, the pair of gears 157 and 159 may be referred to as secondgear combination, and so on.

In the illustrated example, the secondary shaft 146 may be positionedbetween the output shaft 126 and the primary shafts 140, 142 with regardto the y-axis. In this way, the compactness of the system may beincreased. However, other transmission systems layouts may be used, inalternate examples.

The gear 164 is specifically an electric drive interface gear (e.g.,electric machine interface gear) that meshes with a gear 165 in theelectric machine gear set 166. The electric machine gear set 166 mayfurther include a gear 167 that is coupled to the electric machine'soutput shaft 168. In the illustrated embodiment, the electric driveinterface gear 164 forms a double gear unit 169 with the gear 161. Insuch an embodiment, the double gear unit 169 is idly mounted, free tospin, on the second primary shaft 142 and independently rotates thereonwhen it is not engaged by an electric drive clutch 173, described ingreater detail herein. Bearings (e.g., roller bearings such as needleroller bearings) may be used to idly mount, free to spin, the doublegear unit 169 to the second primary shaft 142. In this way, the gearboxachieves greater adaptability. The gears in the electric machine gearset 166 may be radially aligned with the electric machine interface gear164 to increase system compactness. In other words, the gears in theelectric machine gear set 166 and the electric machine interface gear164 may be arranged in a similar position on the x-axis and thereforeare aligned along the x-axis. In this way, the space efficiency of thetransmission is increased, when compared to transmission that may usegears which are offset (with regard to the x-axis) along a layshaft.

Generally, as discussed herein, a component which is idly mounted toanother may utilize one or more bearings (e.g., needle roller bearings,ball bearings, tapered roller bearings, combinations thereof, and thelike) coupled to each component to achieve the idle mountingfunctionality where the component is free to spin on the shaft to whichit is idly mounted. As such, when a gear is idly mounted to a shaft thegear and the shaft independently rotate. Specifically, in theillustrated example, the gears 150, 151, 154, 155, 156, 157 are idlymounted to the secondary shaft 146 via bearings 187. Further in theillustrated example, the gears 163, 179 are idly mounted to the firstprimary shaft 140 via bearings 188. Still further in the illustratedexample, the gears 161, 164 are idly mounted to the second primary shaft142 via a bearing 189. However, other idle mounting arrangements withrespect to the gears in the transmission may be used in otherembodiments. Gears that are engageable with the clutches describedherein may be idly mounted on the shaft associated with the clutch toallow selective mechanical power transfer from the gear to the shaft. Assuch, the other transmission system embodiments described herein includeidly mounted gears and the idly mounting of the gears is drawn in amanner, similar to FIG. 1 and repeated description of idle mounting isomitted for brevity.

The gear ratio drive by the electric machine 108 may be different (e.g.,lower) than the gear ratio drive by the ICE 110. Consequently, an ICEand an electric machine with desired performance characteristics may beselected to enhance transmission performance.

Clutches 170, 171, 172 may be positioned on the secondary shaft 146.Each of the clutches 170, 171, 172 as well as clutch 174 may have twoengaged positions and a disengaged position. When the clutches 170, 171,172 are disengaged they provide no torque transfer between thecorresponding gears and the secondary shaft 146. Conversely, when theclutches 170, 171, 172 are engaged they allow torque to be transferredbetween the gear they are engaging and the secondary shaft 146. When theclutch 174 is engaged it allows torque to be transferred between theengaged gear (either gear 179 or gear 163) and the first primary shaft140.

The clutch 170 may be specifically designed to selectively engage thesixth gear 154 and the fourth gear 155. The clutch 171 may be designedto selectively engage the eighth gear 156 and the second gear 157. Theclutch 172 may be designed to engage the third gear 151 and the firstgear 150. Thus, the first gear, the second gear, the third gear, thefourth gear, the sixth gear, and the eighth gear may be idly mounted,free to rotate, on the secondary shaft 146 such that they are allowed torotate independently from the shaft when the corresponding clutch isdisengaged from the gear. Bearings may be used to idly mount theaforementioned gears on the secondary shaft. Conversely, the gear 158may be fixedly coupled to the first primary shaft 140 for rotationtherewith, the gears 159, 162 may be fixedly coupled to the secondprimary shaft 142 for rotation therewith, and the fifth gear 153 and theseventh gear 152 may be fixedly coupled to the secondary shaft 146 forrotation therewith. However, the gears in the multi-speed gearbox mayhave a different configuration with regard to fixed and idle attachmentwith their corresponding shafts, in other embodiments.

The clutch 174 may further be positioned on the first primary shaft 140.The clutch 174 is designed with two engagement positions. In the firstengagement position, the clutch 174 couples the gear 179 to the firstprimary shaft 140 and in the second engagement position the clutchcoupled the gear 163 to the first primary shaft. In this way, thetransmission can shift between the fifth and seventh gears on thesecondary shaft 146. The clutches 170, 171, 172, and 174 may be referredto as gear clutches.

The clutches 170, 171, 172, 174 as well as the remainder of the clutchesdescribed herein may be generally referred to as coupling devices.Further, the clutches 170, 171, 172, 174 as well as the remainder of theclutches described herein with regard to FIG. 1 as well as the remainderof the figures may be dog clutches, sliding sleeve clutches,synchronizers, or other combinations of these clutch types. A dog clutchmay include protrusions on opposing axial faces of components in theclutch. A sliding sleeve clutch may include circumferential teeth onouter and inner clutch rings that mate with one another during clutchengagement and a synchronizer may include a synchronizer ring or othermechanism that allows the speed of the gear and the shaft to be matchedprior to or during clutch engagement. Further, the clutches 170, 171,172, 174 as well as the remainder of the clutches described herein maybe actuated via electro-mechanical components, hydraulic components,and/or pneumatic components. Specifically, in one example, the clutchesmay be adjusted via shift forks, although other suitable actuationmechanisms have been contemplated.

Additionally, the electric drive clutch 173 may be concentric to thefirst and second primary shafts 140, 142. The electric drive clutch mayspecifically be a synchronizer, in one example, to facilitate smoothtransitions between clutch disengagement and engagement. However, aspreviously discussed, the electric drive clutch may be a dog clutch or asliding sleeve clutch, in other examples. The electric drive clutch 173is designed to operate in a disengaged position where it is decoupledfrom the double gear unit 169 and therefore the electric drive interfacegear 164. When the electric drive clutch 173 is disengaged, themechanical power path from the electric machine 108 may therefore bypassthe primary shafts 140, 142 and travel to the secondary shaft 146 viathe gear 164 or the gear 161. Conversely, when the electric drive clutch173 is engaged the double gear unit 169 is coupled for rotation with thesecond primary shaft 142. As such, when the electric drive clutch isengaged, mechanical power travels between the electric machine 108 tothe second primary shaft 142. In this way, the electric machine can havea wider number of operating gears and the power from the electricmachine may be introduced into different locations in the system. As aresult, the transmission's adaptability is increased which may allow forthe transmission's efficiency and performance to be increased, ifdesired.

The electric drive clutch 173 may be positioned along the primary shafts140, 142 in a similar axial position with regard to the clutch 170 whenthe clutches are in a disengaged position. In this way, the clutches maybe efficiently packaged in the multi-speed gearbox 106.

Further, in the transmission system 104, the ICE 110, the flywheel 138,and the dual-clutch assembly 118 may be provided proximate a first end175 of the first primary shaft 140. Further, the electric drive clutch173 is spaced away from the second end 176 of the first primary shaft140. In this way, the electric machine may be placed on a lateral sideof the transmission system 104, thereby decreasing the longitudinallength of the transmission, along an axis parallel to the x-axis, whencompared to a hybrid transmission having a P2 type architecture when themotor is arranged between transmission's input clutch and the engine.The wheelbase 177 of the vehicle 100 may be consequently decreased, ifdesired. Further, the system may be more easily incorporated into thevehicle's frame when its axial length is decreased, when compared totransmission with longer axial lengths. Further, in comparison totransmission systems with P2 architectures, the transmission system 104may have less rotating components during the EV mode when compared to P2transmission systems. The transmission arrangement shown in FIG. 1 maybe referred to as a P2.5 or P2/P3 hybrid architecture, in someinstances. For instance, in the EV mode and the kinetic energy recoverymode, the first primary shaft 140, the gears 150, 151, as well as theirrespective bearings may not rotate. Further, in these modes and when thegearbox is operating in the fourth gear or the eighth gear, a mechanicalpump linked directly to a clutch basket associated with the doubleclutch may not rotate. Additionally, when the gearbox is operating inthe fourth gear in the EV mode, the second primary shaft 142 may notrotate. Transmission efficiency is increased as a result. Additionally,with the transmission system 104 in the ICE mode where the electricmachine 108 does not provide power to the transmission, it is possible,at least in certain gears, to decouple the electric machine from thetransmission as opposed to P2 style transmission architectures wheredecoupling the motor from the transmission is not possible.

The multi-speed gearbox 106 may further include a park lock assembly 178that is designed to selectively inhibit motion of a parking sprocket 180that is coupled to the output shaft 126. To accomplish thisfunctionality, the park lock assembly 178 may include a parking pawland/or other suitable mechanisms that engage the parking sprocket 180when park lock is activated.

The vehicle 100 may further include a control system 190 with acontroller 191. The controller 191 includes a processor 192 and a memory193. The memory 193 may hold instructions stored therein that whenexecuted by the processor cause the controller 191 to perform variousmethods, control techniques, and the like described herein. Theprocessor 192 may include a microprocessor unit and/or other types ofcircuits. The memory 193 may include known data storage mediums such asrandom access memory, read only memory, keep alive memory, combinationsthereof, and the like.

The controller 191 may receive various signals from sensors 194 (e.g.,speed sensors, pressure sensors, clutch configuration sensors,temperature sensors, and the like) positioned in the vehicle 100 (e.g.,the powertrain 102 and specifically the transmission system 104).Conversely, the controller 191 may send control signals to variousactuators 195 at different locations in the vehicle and transmissionsystem, for clutch engagement, gear shifting, electronic differentialactuation, and the like, for instance, based on received signals andinstructions stored in the memory 193 of the controller 191. Forinstance, the controller 191 may send command signals to the electricdrive clutch 173 or an actuator of the clutch. Responsive to theelectric drive clutch 173 receiving the command signal, the clutch'sactuator may be used to shift the clutch its engaged position. The othercontrollable components in the transmission such as an electric pump,solenoid valves, and the like, and more generally the vehicle, may beoperated in a similar manner with regard to sensor signals and actuatoradjustment. Further, the controller 191 may be designed to executeinstructions for shifting the gearbox clutches into positions thatachieve the power paths in the different modes discussed in greaterdetail herein. For instance, the controller 191 may be designed todisengage the dual-clutch assembly 118 and engage the clutch 170 or theclutch 171 in an EV mode. The components that may be adjusted by thecontroller 191 may include the clutches 170, 171, 172, 173, 174, thepark lock assembly 178, the inverter 114, the electric machine 108, theICE 110, the differential 122 in the case of an electronic limited slipdifferential, other external devices/auxiliaries such as an air brakesystem and a suspension system, and the like. However, in otherexamples, separate controllers may adjust at least a portion of thesecontrollable components.

One or more input device(s) 196 may be further included in the controlsystem 190. The input devices 196 may include a gear selector thatpermits the vehicle operator to select an active gear from a group ofdrive gears and/or a forward, reverse, and neutral drive mode. The inputdevices 196 may further include a transmission system mode selector thatpermits the operator to select the vehicle's current operating mode froma group of operating modes that may include a hybrid drive mode, an EVmode, and/or an ICE mode. However, in other examples, more automatedtechniques for gear and/or drive mode selection may be used in thetransmission system.

Further, the electric machine 108, as well as being controlled withregard to torque and speed via the inverter, may be designed to be spunin both forward drive and reverse drive directions, which are oppositeone another, to allow the system to achieve electric reversefunctionality. To elaborate, the transmission system 104 may be operatedin a reverse drive mode where the electric machine 108 spins in areverse drive direction to propel the vehicle in a reverse direction.The other transmission systems described herein which do not havemechanical reverse assemblies may also be designed with electric reversefunctionality where the electric machine is designed to rotate inopposing directions. Using electric reverse in the system deceasessystem weight and size when compared to transmission systems usingmechanical reverse assemblies.

An axis system 199 is provided in FIG. 1 , as well as FIGS. 2A-2H and2J-27 , for reference. The z-axis may be a vertical axis (e.g., parallelto a gravitational axis), the y-axis may be a lateral/transverse axis(e.g., horizontal axis), and/or the x-axis may be a longitudinal axis,in one example. However, the axes may have other orientations, in otherexamples.

Further, as discussed in greater detail herein, the architecture of thetransmission system 104 may be highly adaptable and efficiently modifiedto meet end-use design targets for a variety of vehicle platforms. Forinstance, the electric machine may be omitted for full ICE vehicleplatforms. In other examples, the dual-clutch assembly may beefficiently replaced with a single clutch assembly for automated manualtransmission (AMT) platforms or manual transmission (MT) platforms.

In the dual-clutch transmission, shown in FIG. 1 , the gear shifting canbe semi-automatic, through the paddles (or other suitable input devices)commanded by the driver, or pure automatic. In manual transmission (MT)the shifting system, intended as the driver interface, must be reviewed,by replacing the paddles with for example a gear lever, a stick shift,and/or mechanical levers to connect the gear lever to the gearbox andintroducing the clutch pedal so both, ICE clutch actuation and gearshifting are under the control of the driver.

FIGS. 2A-2H depict mechanical power paths through the transmissionsystem 104 in a hybrid drive mode where different gears on the primaryand secondary shaft are preselected by an operator or automatically viaa gear selection algorithm in the controller. As such, in each of FIGS.2A-2H the ICE 110 and the electric machine 108 are operated to generaterotational output. FIGS. 2A-2H specifically represent the first througheighth gears. However, as previously discussed, the transmission systemmay have an alternate number of operating gears and/or other power pathsin the operating gears. Further, the components of the transmissionsystem 104 depicted in FIGS. 2A-2H as well as FIG. 2J and FIGS. 4A-10Dare similarly numbered and redundant description is omitted forconcision.

In FIG. 2A, the transmission system 104 drives the first gear 150 in ahybrid drive mode, with a first gear power path 200. Specifically, inthe first gear, the first clutch mechanism 143 in the dual-clutchassembly 118 is engaged to lock the ICE 110 for rotation with the firstprimary shaft 140, the clutch 172 is engaged with the first gear 150,the electric drive clutch 173 is engaged, and the clutch 171 is engagedwith the second gear 157. The remainder of the clutches 170, 174 aredisengaged in their neutral positions.

The first gear power path 200 unfolds as follows: power is transferredfrom the ICE 110 to the first clutch mechanism 143 of the dual-clutchassembly 118 to the first primary shaft 140. Next, the power path 200moves through the first primary shaft 140 to the first gear 150 by wayof the gear 158 fixed to the first primary shaft, and continues totravel through the secondary shaft 146 to the fifth gear 153.

Next, power is transferred from the fifth gear 153 to the output shaft126 by way of the drop gear 127. Thus, from the output shaft 126, poweris transferred to the differential 122. Further, it will also beunderstood that the power path may travel through the differential tothe axle shafts 134 and to the drive wheels 124. In each of theoperating gears, the portion of the power path from the fifth gear 153to the differential 122 via the output shaft 126 is identical, andredundant description is omitted for brevity.

The power path 200 further includes an electric drive branch 202, thattravels from the electric machine 108 to the electric machine gear set166, from the electric machine gear set to the electric drive interfacegear 164, from the electric drive interface gear to the second primaryshaft 142 vis the electric drive clutch 173, from the second primaryshaft to the gear 159, from the gear 159 to the second gear 157, fromthe second gear to the secondary shaft 146, and from the secondary shaftto fifth gear 153. The first gear power path allows the electric machineto drive the second gear while the ICE drives the first gear.Consequently, the electric machine and the internal combustion enginemay be more efficiently operated.

In FIG. 2B, the transmission system 104 drives the second gear 157 in ahybrid drive mode, with a second gear power path 204. Specifically, inthe second gear, the second clutch mechanism 144 in the dual-clutchassembly 118 is engaged to lock the ICE 110 for rotation with the secondprimary shaft 142, the electric drive clutch 173 is engaged with thedouble gear unit 169, and the clutch 171 is engaged with the second gear157. The remainder of the clutches 170, 172, 174 are disengaged in theirneutral positions.

The second gear power path 204 unfolds as follows: power is transferredfrom the ICE 110 to the second clutch mechanism 144 of the dual-clutchassembly 118 to the second primary shaft 142. Next, the power path 204moves through the second primary shaft 142 to the second gear 157 by wayof the gear 159 that is fixed to the secondary shaft 146. Next, thepower moves from the second gear 157 to the secondary shaft 146, fromthe secondary shaft to the fifth gear 153.

The power path 204 further includes an electric drive branch 206, thattravels from the electric machine 108 to the electric machine gear set166, from the electric machine gear set to the electric drive interfacegear 164, and from the electric drive interface gear to the secondprimary shaft 142. In other second gear configurations, the ICE 110 mayrun the second gear while the electric machine 108 runs another gearsuch as the fourth gear, thereby increasing the system's adaptabilityand performance, if wanted.

In FIG. 2C, the transmission system 104 drives the third gear 151 in ahybrid drive mode, with a third gear power path 208. Specifically, inthe third gear, the first clutch mechanism 143 in the dual-clutchassembly 118 is engaged to lock the ICE 110 for rotation with the firstprimary shaft 140, the clutch 170 is engaged with the fourth gear 155,and the clutch 172 is engaged with the third gear 151. The remainder ofthe clutches 171, 174 as well as the electric drive clutch 173 aredisengaged in their neutral positions.

The third gear power path 208 unfolds as follows: power is transferredfrom the ICE 110 to the first clutch mechanism 143 of the dual-clutchassembly 118 and then to the first primary shaft 140. Next, the powerpath 208 moves through the first primary shaft 140 to the third gear 151by way of the gear 163 that is fixed to the first primary shaft 140.Next, the power path travels from the third gear 151 to the secondaryshaft 146 and from the secondary shaft 146 to the fifth gear 153.

The power path 208 further includes an electric drive branch 210, thattravels from the electric machine 108 to the electric machine gear set166, from the electric machine gear set 166 to the electric driveinterface gear 164, from the electric drive interface gear 164 to thesecondary shaft 146 via the fourth gear 155 by way of gear 161. Next theelectric drive branch 210 of the power path travels from the secondaryshaft to the fifth gear 153.

In FIG. 2D, the transmission system 104 drives the fourth gear 155 in ahybrid drive mode, with a fourth gear power path 212. Specifically, inthe fourth gear, the second clutch mechanism 144 in the dual-clutchassembly 118 is engaged to lock the ICE 110 for rotation with the secondprimary shaft 142 and the clutch 170 is engaged with the fourth gear155. The remainder of the clutches 171, 172, 174 as well as the electricdrive clutch 173 are disengaged in their neutral positions.

The fourth gear power path 212 unfolds as follows: power is transferredfrom the ICE 110 to the second clutch mechanism 144 of the dual-clutchassembly 118 to the second primary shaft 142. Next, the power path 212moves through the second primary shaft 142 to the fourth gear 155 by wayof the gear 161. Next, the power path travels from the fourth gear 155to the secondary shaft 146 and from the secondary shaft 146 to the fifthgear 153.

In the electric drive branch 214 of the power path 212, power travelsfrom the electric machine 108 to the electric machine gear set 166, fromthe electric machine gear set to the electric drive interface gear 164,and from the electric drive interface gear to the fourth gear 155 by wayof gear 161, bypassing the primary shafts.

In FIG. 2E, the transmission system 104 drives the fifth gear ratio 153in a hybrid drive mode, with a fifth gear power path 216. Specifically,in the fifth gear, the first clutch mechanism 143 in the dual-clutchassembly 118 is engaged to lock the ICE 110 for rotation with the firstprimary shaft 140, the clutch 170 is engaged with the sixth gear 154,the electric drive clutch 173 is engaged with the double gear unit 169and the second primary shaft 142, and the clutch 174 is engaged with thegear 179. The remainder of the clutches 171, 172 are disengaged in theirneutral positions.

The fifth gear power path 216 unfolds as follows: power is transferredfrom the ICE 110 to the first clutch mechanism 143 of the dual-clutchassembly 118 to the first primary shaft 140. Next, the power path 216moves through the first primary shaft 140 to the fifth gear 153 by wayof the gear 179.

In the electric drive branch 218 of the power path 216, power travelsfrom the electric machine 108 to the electric machine gear set 166, fromthe electric machine gear set to the electric drive interface gear 164,from the electric drive interface gear to the second primary shaft 142via the electric drive clutch 173, and from the second primary shaft tothe gear 162. Next the power path travels to the sixth gear 154 by wayof the gear 162 that is coupled to the second primary shaft 142. Fromthe sixth gear 154 power moves through the secondary shaft 146 to thefifth gear 153 in the electric drive branch 218.

In FIG. 2F, the transmission system 104 drives the sixth gear 154 in ahybrid drive mode, with a sixth gear power path 220. Specifically, inthe sixth gear, the second clutch mechanism 144 in the dual-clutchassembly 118 is engaged to lock the ICE 110 for rotation with the secondprimary shaft 142, the electric drive clutch 173 is engaged with thedouble gear unit 169 and the second primary shaft 142, and the clutch170 is engaged with the sixth gear 154. The remainder of the clutches171, 172, 174 are disengaged in their neutral positions.

The sixth gear power path 220 unfolds as follows: power is transferredfrom the ICE 110 to the second clutch mechanism 144 of the dual-clutchassembly 118 to the second primary shaft 142. Next, the power path 220moves through the second primary shaft 142 to the sixth gear 154 by wayof the gear 162 that is coupled to the second primary shaft 142. Nextthe power path travels from the second primary shaft 142 to the gear162, from the gear 162 to the sixth gear 164, from the sixth gear to thesecondary shaft 146, and from the secondary shaft 146 to the fifth gear153.

In the electric drive branch 222 of the power path 220, power travelsfrom the electric machine 108 to the electric machine gear set 166, fromthe electric machine gear set to the electric drive interface gear 164,and from the electric drive interface gear 164 to the second primaryshaft 142 by way of the electric drive clutch 173.

In FIG. 2G, the transmission system 104 drives the seventh gear 152 in ahybrid drive mode, with a seventh gear power path 224. Specifically, inthe seventh gear, the first clutch mechanism 143 in the dual-clutchassembly 118 is engaged to lock the ICE 110 for rotation with the firstprimary shaft 140, the clutch 174 is engaged with the gear 163, and theclutch 171 is engaged with the fourth gear 154. The remainder of theclutches 171, 172, 173 are disengaged in their neutral positions.

The seventh gear power path 224 unfolds as follows: power is transferredfrom the ICE 110 to the first clutch mechanism 143 of the dual-clutchassembly 118 and then to the first primary shaft 140. Next, the powerpath 224 moves through the first primary shaft 140 to the seventh gear152 by way of the gear 163 that is locked for rotation with the firstprimary shaft 140 via the clutch 174. Next power travels through thesecondary shaft 146 to the fifth gear 153.

In the electric drive branch 226 of the power path 224, power travelsfrom the electric machine 108 to the electric machine gear set 166, fromthe electric machine gear set to the electric drive interface gear 164,from the electric drive interface gear to the eighth gear 156, from theeighth gear to the secondary shaft 146, and from the secondary shaft tothe fifth gear 153.

In FIG. 2H, the transmission system 104 drives the eighth gear 156 in ahybrid drive mode, with an eighth gear power path 228. Specifically, inthe eighth gear, the second clutch mechanism 144 in the dual-clutchassembly 118 is engaged to lock the ICE 110 for rotation with the secondprimary shaft 142 and the clutch 171 is engaged with the eighth gear156. The remainder of the clutches 170, 172, 174 as well as the electricdrive clutch 173 are disengaged in their neutral positions.

The eighth gear power path 228 unfolds as follows: power is transferredfrom the ICE 110 to the second clutch mechanism 144 of the dual-clutchassembly 118 to the second primary shaft 142. Next, the power path 228moves through the second primary shaft 142 to the eighth gear 156 by wayof the electric drive interface gear 164. Next power travels through thesecondary shaft 146 to the fifth gear 153.

In the electric drive branch 230 of the power path 228, power travelsfrom the electric machine 108 to the electric machine gear set 166, fromthe electric machine gear set to the electric drive interface gear 164,and from the electric drive interface gear to the eighth gear 156.

FIG. 2I illustrates a table 240 corresponding to an ICE mode, hybriddrive mode and an EV mode for the transmission system 104, depicted inFIGS. 1-2H. The columns of the table 240 indicates the selected gear,the gear driven by the ICE 110, and the gear drive by the electricmachine 108 during upshifting and downshifting. Additionally, with otherlayouts different modes can be obtained, if wanted. Different drivingstrategies may be adopted to increase fuel economy or performance.

In the ICE mode, the ICE 110 may drive the first gear, the second gear,and the sixth gear. Further, in the ICE mode, the ICE 110 may drive thethird gear, the fifth gear, and the seventh gear if the fourth or eighthgear has not been preselected.

In the illustrated example, during an up-shift when the second gear orthird gear is preselected, the electric machine 108 may drive either thesecond gear or the fourth gear while the ICE 110 transitions from itscurrent operating gear to the selected gear. Further, during an up-shiftwhen the sixth gear or the seventh gear is preselected, the electricmachine 108 may drive either the sixth gear or the eighth gear.

Conversely, during a down-shift when the first gear or the second gearis preselected, the electric machine 108 may drive either the secondgear or the fourth gear. Further, during a down-shift when the fifthgear or the sixth gear is preselected, the electric machine may driveeither the sixth gear or the eighth gear.

Table 240 further shows the gearing for the ICE 110 and the electricmachine 108 in a mode where no gear is preselected. In this operatingmode, when the ICE 110 is driving the first gear, the electric machine108 may drive the first gear, the second gear, the fourth gear, thesixth gear, or the eighth gear. Further, in such an operating mode whenthe ICE is driving the second gear, the electric machine may drive thesecond gear or the fourth gear. Further, when the ICE is driving thethird gear, the electric machine may drive the second gear, the thirdgear, the fourth gear, the sixth gear, or the eighth gear.

Additionally, when no gear is preselected and when the ICE is drivingthe fourth gear, the electric machine may drive the fourth gear. Whenthe ICE is driving the fifth gear, the electric machine may drive thesecond gear, the fourth gear, the fifth gear, the sixth gear, or theeighth gear. Still further, when the ICE is driving the sixth gear, theelectric machine may drive the sixth gear or the eighth gear. When theICE is driving the seventh gear, the electric machine may drive thesecond gear, the fourth gear, the sixth gear, the seventh gear, or theeighth gear. Further, when the ICE drives the eighth gear, the electricmachine may similarly drive the eighth gear.

Table 240 further shows the gearing for the electric machine 108 in anEV mode where the ICE is not operational. As depicted, the electricmachine 108 may be operated in any of the even gears during the EV mode.Further, in certain transmission architectures, such as the transmissionsystems, shown in FIGS. 17 and 18 which are described in greater detailherein, the electric machine may also be operated in the odd gearsduring the EV mode.

Additionally, during a mode where engine cranking is occurring, the EVmode is active, and the vehicle is in motion, the ICE may be crankedusing the first or second clutch mechanism in the dual-clutch assembly.Consequently, the system may transition to the hybrid mode from the EVmode over a wide range of operating conditions.

It will be understood that in certain examples, the transmission system104 may achieve over one hundred distinct full ICE, hybrid, and EVmodes, although the end-user may not utilize all the modes. Thus, thetransmission has a high level of adaptability.

FIG. 2J shows bearings 250 coupled to the second primary shaft 142 and abearing 252 coupled to the end 176 of the first primary shaft 140. Asdescribed herein a bearing supports and permits rotation of thecomponent to which it is attached and may include inner and outer racesas well as rolling elements (e.g., balls, cylindrical rollers, taperedcylindrical rollers, and the like). Further, bearings 254 are coupled tothe secondary shaft 146, in the illustrated embodiment. Bearings 256 arefurther coupled to the shafts 257 and 168 that are coupled to theelectric machine gear set 166. The abovementioned bearings may be ballbearings, although other types of bearings have been contemplated.

Bearings 258, 260, 262 may be further coupled to the output shaft 126.The bearings 260, 262 are specifically illustrated as tapered rollerbearings and the bearing 258 is illustrated as a cylindrical rollerbearing, although other types of bearings may be used in the system inother embodiments. The layout, number, and/or types of bearings in thesystem may be altered in other embodiments. Bearings 264 may also becoupled to the differential 122. At least a portion of the bearings inthe transmission system may form a set of bearings.

FIGS. 4A-4E show a shifting strategy for the transmission system 104where the multi-speed gearbox 106 is shifted from the second gear 157 tothe third gear 151 and then from the third gear to the fourth gear 155,while the system is operating in a hybrid mode. Further, mechanicalpower paths 400, 402, 404, 406, 408 are shown in FIGS. 4A-4E,respectively. Specifically, as shown in FIG. 4A, the transmission system104 is operating in the second gear 157. As such, the clutch 171 engagesthe second gear 157 and the clutch 172 engages the third gear 151 inanticipation of the upshift to the third gear. Further, the electricdrive clutch 173 is engaged in FIG. 4A and the second clutch mechanism144 in the dual-clutch assembly 118 is engaged. The system enablesseamless gear shifting and powershifting, if so desired.

Next in FIG. 4B, the first clutch mechanism 143 in the dual-clutchassembly 118 is engaged while the second clutch mechanism 144 isdisengaged to allow power to be transferred from the ICE 110 to thethird gear 151, while engagement of the electric drive clutch issustained. During this dual-clutch shifting event, the electric machine108 continues to drive the second gear 157.

Next in FIG. 4C, the clutch 171 is disengaged from the second gear 157,the electric drive clutch 173 is disengaged, and the ICE 110 continuesto transfer power to the third gear 151. Next in FIG. 4D, the clutch 170is engaged with the fourth gear 155 and power is transferred from theelectric machine 108 to the fourth gear.

Next in FIG. 4E, the second clutch mechanism 144 in the dual-clutchassembly 118 is engaged, the electric drive clutch 173 is engaged, andthe first clutch mechanism 143 is disengaged to allow power to travelfrom the ICE 110 as well as the electric machine 108 to the fourth gear155. In this way, the gearbox can be smoothly and efficiently shiftedbetween the odd and even gears. Specifically, as shown in FIGS. 4D and4E the electric machine 108 can provide continuous power transfer to thedrive wheels while the dual-clutch assembly 118 shifts the gears drivenby the ICE 110, referred to as electric-boost functionality.

FIGS. 5A, 5B, and 4E show another shifting strategy that may beimplemented in the transmission system 104. In this shifting sequencethe multi-speed gearbox 106 is shifted from the second gear 157 to thethird gear 151 (and then to the fourth gear, as shown in FIG. 4E) whilethe transmission system 104 is operating in the hybrid mode. In thismaneuver, opposed to the aforementioned shifting strategy, the electricmachine 108 may continuously provide electric boost to the transmissionand there may be no torque drop while the ICE shifts from the secondgear to the third gear and then from the third gear to the fourth gear.Further, mechanical power paths 500, 502 are shown in FIGS. 5A-5B,respectively. Specifically, as shown in FIG. 5A, power is transferredfrom the ICE 110 to the second gear 157 while power is transferred fromthe electric machine 108 to the fourth gear 155. Further, as shown inFIG. 5A, the clutch 172 is engaged with the third gear 151 inanticipation of a shift. The system enables seamless gear shifting andpowershifting, if desired.

To shift from the second gear to the third gear, the second clutchmechanism 144 in the dual-clutch assembly is disengaged while the firstclutch mechanism 143 is engaged, as shown in FIG. 5B. Several gearshifting strategy including different clutch control strategies such asclutch cross-shifting may be adopted in order to obtain a smoothseamless shifting or a fast seamless shifting. As such, power flows fromthe ICE 110 to the third gear while power flows from the electricmachine 108 to the fourth gear. In this way, the electric machine canprovide electric boost functionality, when desired, thereby increasingsystem performance. To elaborate, the multi-speed gearbox may beconfigured to enable the electric machine 108 to drive a gear that ishigher than, lower than, or the same as the gear driven by the ICE. Inthis arrangement, the electric machine achieves a similar functionalityto hybrid systems with P3 type architectures where the motor is coupledto the transmission's output shaft. To elaborate, in the abovementionedconditions, the electric-boost functionality may be provided in thefirst through fourth gears. Consequently, the system's performance isenhanced.

FIG. 6 shows the transmission system 104 operating in another mode whereboth the electric machine 108 and the ICE 110 transfer power to an oddgear on the secondary shaft 146 in a hybrid mode with a power path 600.To elaborate, both the electric machine 108 and the ICE 110 aretransferring power to the third gear 151. However, it will beappreciated that the system may also transfer power to the first gear150, the fifth gear 153, and the seventh gear 152, in a similar manner.To accomplish this odd gear power transfer, the electric drive clutch173 is engaged and power travels from the electric machine 108 to thesecond primary shaft 142 and from the second primary shaft to thedual-clutch assembly 118 where the power is combined with power from theICE and transferred to the first primary shaft 140. In this way, theoptions for the system's driven gears in the hybrid mode is expanded, toallow for further gains in system performance.

FIGS. 7A-7C show the transmission system 104 operating in differentcranking modes where the electric machine 108 is used to induce start-upin the ICE 110. Generally, during cranking the electric machine 108 maydrive the second gear 157, the fourth gear 155, the sixth gear 154, orthe eighth gear 156. Further, cranking operation may be performedthrough either of the clutches in the dual-clutch assembly 118 while thevehicle is in motion.

Power paths 700, 702, and 704 are shown in FIGS. 7A-7C, respectively.Specifically, as shown in FIG. 7A, power is transferred from theelectric machine 108 to the second primary shaft 142 by way of theelectric drive clutch 173, which is engaged. From the second primaryshaft 142 power is transferred to the ICE via the dual-clutch assembly118. Further, in the mode shown in FIG. 7A, the clutches 170, 171, 172,174 are disengaged. The cranking mode shown in FIG. 7A may be used whilethe vehicle is at standstill (e.g., at or approaching zero speed).

FIGS. 7B-7C show cranking modes that can be implemented while thevehicle is in motion (e.g., vehicle speed is greater than zero).Specifically, in both cranking modes, power is transferred from theelectric machine 108 to the ICE 110 as well as the differential 122. Asshown specifically, in FIG. 7B, the power is transferred from theelectric machine 108 to the dual-clutch assembly 118 via the secondprimary shaft 142 and to the fourth gear 155 via the second primaryshaft 142. As such, in FIG. 7B the electric drive clutch 173 is engaged.Conversely, in FIG. 7C the electric drive clutch 173 is disengaged, theclutch 170 is engaged with the fourth gear 155, and the clutches 171,172, 174 are disengaged.

Further, in FIG. 7C, power is transferred from the electric machine 108to the fourth gear 155 and from the fourth gear to the secondary shaft146. From the secondary shaft 146, the power is split and transferred toboth the drop gear 127 and the seventh gear 152. Next the power pathtravels to the first primary shaft 140 and then to the dual-clutchassembly 118 via the first clutch mechanism 143. In this way, the ICEmay be cranked using different gear ratios. Thus, in FIG. 7C the clutch174 is engaged with the gear 163, the clutch 170 is engaged with thefourth gear 155, and the clutches 171, 172, 173 are disengaged. Furtherit will be understood that other gears or gear combinations may be usedto crank the ICE 110.

FIGS. 8A-8D depict the transmission system 104 operating in an EV modewhile in different operating gears (i.e., the second gear, the fourthgear, the sixth gear, and the eighth gear). Power paths 800, 802, 804,and 806 are shown in FIGS. 8A-8D, respectively. It will be understoodthat in the EV mode, the ICE 110 may be shut down and/or decoupled fromthe dual-clutch assembly 118 and the electric machine 108 is generatingmechanical power. In the EV mode, the power paths may either bypass ortravel through the secondary shaft 146 depending on performance targets,allowing the system's performance to be fine-tuned depending on vehicleoperating conditions, for instance. Further, in other kinematictransmission layouts, such as those shown in FIGS. 17-18 , the electricmachine may be operated in the odd gears during the EV mode due to theability of these transmissions to link the inner and outer primaryshafts.

FIG. 8A shows the transmission system 104 in the second gear 157 wherethe clutch 171 engages the second gear 157, the electric drive clutch173 is engaged, and the remainder of the clutches are disengaged. Thesecond gear EV mode may be used when comparatively high torque isdesired while the vehicle is on a slope or off the line acceleration.

FIG. 8B shows the transmission system 104 in the fourth gear 155 wherethe clutch 170 engages said gear and the remainder of the clutches aredisengaged. In the fourth gear, the power path from the electric machine108 bypasses the second primary shaft 142 and flows to the secondaryshaft 146. The fourth gear EV mode may be implemented when higherdriveline system efficiency is wanted.

FIG. 8C shows the transmission system 104 in the sixth gear 154 wherethe clutch 170 engages said gear, the electric drive clutch 173 isengaged, and the remainder of the clutches are disengaged. As such, inthe sixth gear EV mode, the power path 806 travels from the electricdrive interface gear 164 to the second primary shaft 142 and then to thesixth gear 154.

FIG. 8D shows the transmission system 104 in the eighth gear 156 wherethe clutch 171 engages said gear and the remainder of the clutches aredisengaged. The eighth gear EV mode may be implemented when higher motorefficiency is wanted. In the eighth and fourth gear EV modes, the systemmay function similarly to a P3 hybrid drive system. The transmissionsystem may shift between the second gear, the fourth gear, the sixthgear, and the eighth gear by disengaging the clutch associated with thecurrent operating gear while engaging the clutch corresponding to thedesired (e.g., selected) operating gear. The electric drive clutch 173may also be engaged to allow power to be transferred to the secondprimary shaft in the second gear and the sixth gear and disengaged toallow power to bypass the second primary shaft in the fourth gear andthe eighth gear.

FIGS. 9A-9B show the transmission system 104 operating in an energystorage device (e.g., battery) charging mode while the vehicle is atstandstill and while the vehicle is in motion, respectively. Therefore,in the charging mode, the ICE 110 is operational and the electricmachine 108 generates electrical energy and transfers said energy to theenergy storage device 112.

In the system configuration shown in FIG. 9A, the electric drive clutch173 is engaged with the double gear unit 169 while the remainder of theclutches in the system are engaged. Specifically, FIG. 9A shows acharging power path 900 which travels from the ICE 110 to the firstprimary shaft 140 via the dual-clutch assembly 118 and then to theelectric machine 108 by way of the electric drive interface gear 164 andthe electric machine gear set 166.

In the transmission system configuration shown in FIG. 9B, the electricdrive clutch 173 is engaged and the clutch 171 engages the second gear157 while the remainder of the clutches are disengaged. The chargingpower path 902 therefore travels along the first primary shaft 140 andsplits, with one branch traveling to the electric machine 108 and theother branch traveling to the second gear 157. It will be understood,that the electric machine may charge the energy storage device in asimilar manner while the system is operating in the other evenlynumbered gears (i.e., the fourth gear, the sixth gear, or the eighthgear).

FIGS. 10A-10D show the transmission system 104 operating in a kineticenergy recovery mode where power travels from the output shaft 126 tothe electric machine 108 for electrical energy generation, for exampleduring braking. As such, in the kinetic energy recovery mode the ICE 110is shut down and/or otherwise decoupled, and/or coupled with the gearboxbut is driven by the output tires (in coasting or sailing, for example),from the gearbox and the electric machine 108 is generating electricalenergy. The power paths 1000, 1002, 1004, and 1006 shown in FIGS.10A-10D are similar to the power paths 800, 802, 804, and 806 shown inFIGS. 8A-8D except reversed. Therefore, redundant description is omittedfor brevity.

FIGS. 2A-10D provide for transmission operating methods that allow thetransmission to be operated in a hybrid mode, an EV mode, an energystorage device charging mode, a kinetic energy recovery mode, and an ICEcranking mode. In the hybrid mode, the method may include operating thesystem in any of the aforementioned gears (e.g., first gear througheighth gear) as well as transitioning between any of two operating gearsvia an upshifting or downshifting operation. To shift between the gears,a gear clutch on the primary shafts and/or the secondary shaft may beengaged with a preselected gear. Next, during the shifting transient, apowershift or a seamless shift may be performed where one of the clutchmechanisms in the dual-clutch assembly is disengaged while the otherclutch mechanism is engaged. The method may further include steps wherepower is transferred between the system components to achieve any of thepower paths described with regard to FIGS. 2A-2H and 4A-10D.

Further, in at least a portion of the system's operating gears, theelectric machine may drive a different gear than the ICE, if wanted. Thegear driven by the electric machine in these operating gears may beswitched based on system operating conditions, torque demands, desiredsystem efficiency, and also depending on the vehicle set-up such astrack mode, comfort mode, eco mode, and the like.

FIG. 11 shows another example of a transmission system 1100 that mayinclude some components that are similar to the transmission system 104depicted in FIG. 1 . Redundant description of the overlapping componentsin the transmission systems shown in FIG. 1 as well as 3, 12-19 and 27is omitted for concision.

The transmission system 1100 shown in FIG. 11 includes a mechanicalreverse assembly 1102 that is coupled to the first primary shaft 140 andthe secondary shaft 146. Further, the transmission system 1100 may againbe a dual-clutch transmission. To elaborate, the mechanical reverseassembly 1102 include a reverse gear set 1104 with a gear 1106 coupledto first primary shaft 140, a gear 1108 idly coupled to the secondaryshaft 146 when a reverse clutch 1110 is disengaged, and a gear 1112 thatmeshes with the gears 1106, 1108. The reverse clutch 1110 is designed tocouple the gear 1108 to the secondary shaft 146 for rotation therewithwhen engaged. Conversely, when the reverse clutch is disengaged, thegear 1108 is allowed to independently rotate with regard to thesecondary shaft 146. In this way, the transmission system 1100 may beselectively placed in a reverse drive mode when desired.

FIG. 12 shows yet another example of a transmission system 1200. Thetransmission system 1200 includes a single primary shaft 1202 and ICEclutch 1204 that is designed to selectively engage the primary shaft forrotation with the ICE. Thus, the transmission system 1200 may be anautomated manual transmission. Further, the electric drive interfacegear 1206 is fixedly coupled to the primary shaft 1202 and meshes withthe eighth gear 156. Further, the gear 1208 is fixedly coupled to theprimary shaft 1202 and meshes with the fourth gear 155. Even further,the gear 1210 is fixedly coupled to the primary shaft 1202 and mesheswith the sixth gear 154 and the gear 1212 is fixedly coupled to theprimary shaft and meshes with the second gear 157. The layout of theclutches and the remainder of the gears in the transmission system 1200is similar to the transmission system 104, shown in FIG. 1 .

FIG. 13 shows yet another example of a transmission system 1300 with anindependent drop gear 1302 that is fixedly coupled to the output shaft126. The transmission system 1300 may again be a dual-clutch typetransmission. The drop gear 1302 meshes with the gear 1304 that isfixedly coupled to the secondary shaft 146. Thus, in the transmissionsystem 1300 the gear 1304 is separate from the fifth gear 152.Therefore, the transmission system 1300 has a longer axial length andgreater weight when compared to the transmission system 104, shown inFIG. 1 . However, the gear ratios may be easier to adjust in thetransmission system 1300. Further, the park lock assembly has beenomitted from the transmission system 1300. However, the park lockassembly may be an optional feature in any of the transmission systemsdescribed herein.

FIG. 14 shows another example of a transmission system 1400 with asingle ICE clutch 1402 and an electric drive clutch 1404 that isdesigned to engage and disengage the double gear unit 169 from theprimary shaft 1406. In this layout the torque fill capability from theelectric motor during gearshifts may be desired for shifting smoothness.Using the electric drive clutch in this automated manual transmissionallows the efficiency of the system's EV mode to be increased whencompared to the single clutch transmission system shown in FIG. 12 .

FIG. 15 shows yet another example of a transmission system 1500. Thetransmission system 1500 is designed as a six speed transmission withthe dual-clutch assembly 118. In the illustrated example, thetransmission system 1500 includes three odd gears 1502 and three evengears 1504 coupled to (e.g., idly or fixedly coupled to) the secondaryshaft 146. In this way, the transmission may be efficiently reconfiguredwith six gear as opposed to the eight gear transmission layout, shown inFIG. 1 .

FIG. 16 shows even another example of a transmission system 1600 thatagain includes a dual-clutch assembly 118 but has ten gears. As such,five even numbered gears 1602 and five odd numbered gears 1604 aremounted on (e.g., idly or fixedly coupled to) the secondary shaft 146.The transmission system 1600 may further include clutch 1606 that allowsthe transmission to shift between the two additional odd gears, whencompared to the previously described eight speed transmission. The tenspeed transmission system 1600 has increased top speed and fuel economywhen compared to the six and eight speed transmissions but alsoincreases the length of the first primary shaft (e.g., the odd gearshaft).

FIG. 17 shows yet another example of a transmission system 1700 with aclutch 1702 (e.g., a dog clutch) designed to selectively engage thesecond primary shaft 142 with the first primary shaft 140. The clutch1702 may be positioned along the second primary shaft 142 at a locationaxially between the electric drive interface gear 164 and the gear 159.The clutch 1702 is designed to selectively couple the second primaryshaft with the first primary shaft while the gear 159 may be fixedlyconnected to the second primary shaft. In this way, the electric machine108 can be connected to the odd gears on the secondary shaft.Consequently, in the EV mode, pull away performance can be increased andenhanced gradeability, if desired. However, adding the clutch 1702 tothe system may increase the axial length of the transmission andincrease the number of components and weight of the system. Adding theclutch 1702 may also increase the likelihood of component degradation,in certain cases.

FIG. 18 shows another example of a transmission system 1800. Thetransmission system 1800 includes a clutch 1802 (e.g., a synchronizer).The clutch 1802 is designed to selectively engage the second primaryshaft 142 and the first primary shaft 140. Again, the system 1800 mayinclude a gear 1804 that meshes with the drop gear 1806 and isindependent from the fifth gear 153. Adding the clutch 1802 may againincrease EV launch performance, in comparison to the dual-clutch layoutsdescribed herein that do not have the ability to selectively couple anddecouple the first and second primary shafts 140, 142. However, it willbe appreciated that the clutch 1802 may be disengaged during certainconditions such as in at least some hybrid mode to avoid a situationwhere the ICE is driving both and odd and even gear.

FIG. 19 shows another example of a transmission system 1900 that againincludes a dual-clutch assembly 118. However, in the transmission layoutshown in FIG. 19 the position of the eight gear 1902 and the fourth gear1904 are swapped in relation to the transmission system 104 shown inFIG. 1 .

FIG. 3 shows another example of a transmission system 300 again with thedual-clutch assembly 118 and the mechanical reverse assembly 1102.However, the electric machine has been omitted in the transmissionsystem 300 depicted in FIG. 3 .

FIG. 27 shows yet another example of a transmission system 2700. Thesystem again has a dual-clutch arrangement but the electric machine gearset 2702 is altered in comparison to the transmission system 104 shownin FIG. 1 . Specifically, the electric machine gear set 2702 includes afirst gear 2704 on the electric machine's output shaft, a second gear2706 that meshes with the first gear, and a third gear 2708 that mesheswith the electric drive interface gear 164. This electric machine gearset arrangement can increase the flexibility for the gear ratio betweenthe electric machine and second primary shaft when compared to theelectric machine gear set 166 shown in FIG. 1 but may also increasesystem weight.

FIG. 20 shows a cross-sectional view of a detailed illustration of atransmission system 2000. The transmission system 2000 may have asimilar layout with regard to gearing and clutches as the transmissionsystem 104, shown in FIG. 1 . Gear clutches 2002, 2004, 2006, and 2008in the gearbox are depicted. Further, the electric drive clutch 2010 isfurther depicted in FIG. 20 that selectively engages the double gear2012 with the second primary shaft 2014.

FIG. 21 shows an exploded view of an exemplary transmission system 2100that has a gearing and clutch architecture similar to the transmissionsystem 104, shown in FIG. 1 . The transmission system 2100 includes ahousing 2102 with sections 2104, 2106, 2108, and 2109. The housingsection 2106 may be contoured to at least partially enclose at least aportion of the gearbox components 2110 such as the primary shafts, thesecondary shaft, the clutches, and the gears residing on the shafts. Anelectric machine 2112 is shown coupled to the housing section 2108.Further, the housing section 2104 may be contoured to enclose thedual-clutch assembly 2114. A clutch control valve module 2115 that isdesigned to actuate the dual-clutch assembly to induce engagement ofboth clutch mechanisms is further illustrated in FIG. 21 . The clutchcontrol valve 2115 may be a hydraulic/mechatronic module, in oneexample. Further a platform approach may be used for the retainingstrategy of the transmission to the vehicle, for example thetransmission mount may be on the housing 2108 (e.g., a geartrainhousing) or a central transmission mount on the housing 2106 (e.g., aclutch housing). Additionally, a shifting system 2116 for actuation ofthe clutches (e.g., synchronizers, dog clutches, sliding sleeveclutches, and the like) in the gearbox is also depicted in FIG. 21 . Ashifting actuation valve module 2117 is further illustrated in FIG. 21 .The shifting system 2116 may include shift forks and rods, for example.However, other suitable shifting system components may be used, in otherexamples.

A differential 2118 as well as a differential shaft 2119 is furtherdepicted in FIG. 21 . The differential 2118 may be an electronic limitedslip differential which increases the vehicle's traction performance andvehicle dynamics through a corner, in one example. However, othersuitable types of differentials have been contemplated. Additionally, acooler 2120, filters 2122, and a pump 2124 are further shown in FIG. 21. However, other transmission system configurations may be used,alternate examples. Arrow 2126 indicates the drive direction of thevehicle. Further, the transmission may be cooled via a dedicated cooler2120, transmission mounted, or an air to oil radiator, vehicle mountedor other cooling systems. In this way, the system's performance may befurther increased, if desired.

FIG. 22 show the housing 2202 with sections 2204, 2206, and 2208. Anelectric machine 2210 is coupled to the housing section 2208.

FIG. 22 further shows the transmission system 2200 with a housing 2202that has sections 2204, 2206, and 2208. The housing section 2206 may atleast partially enclose the primary shafts, the secondary shaft, and theoutput shaft of the transmission and the corresponding gears andclutches. A shaft 2212 that serves as an interface for the flywheel isfurther shown in FIG. 22 . Axle shafts (referred to as driveshafts, insome instances) 2214 are further illustrated in FIG. 22 .

FIGS. 23-26 show vehicles 2300, 2400, 2500, and 2600 respectively, withdifferent front axle, engine, and electric drive configurations.Specifically, as shown in FIG. 23 , the all-wheel drive vehicle 2300 hasa transmission system 2301 with an ICE (or other suitable engine) 2302,gearbox 2304, and electric machine 2306 configured to provide power to arear axle 2308 that includes axle shafts (referred to as driveshafts, insome instances) 2310. The ICE 2302 is shown mounted near the middle ofthe vehicle, although other engine positions have been contemplated.

The transmission system 2301 may have a layout that is similar to thedual-clutch transmission system 104, shown in FIG. 1 , in oneembodiment. However, in alternate embodiments, the transmission system2301 may have a layout similar to any of the transmission systems shownin FIGS. 11-19 . The vehicle 2300 further includes a steerable frontelectric axle assembly 2312 that includes electric machines 2314 thatdrive opposing axle shafts 2316. When, the front axle is operational andthe transmission system 2301 is in neutral, losses in the transmissionsystem are reduced when compared to P2 style hybrid transmissions. Forinstance, when the transmission system is in neutral and the wheelstransfer torque to the gearbox (during a coast or sailing condition, forexample), the output shaft, the secondary shaft, and a portion of thegears that are coaxial to the primary shafts rotate. However, the firstand second primary shafts do not rotate when the transmission system inneutral, thereby increasing powertrain efficiency and reducing coastdown on the rear axle.

FIG. 24 shows the rear wheel drive vehicle 2400 which again includes thetransmission system 2301 but the steerable front axle 2402 does notinclude and electric drive unit. Omitting the front electric drive unitdecreases the system's weight and complexity as well as the likelihoodof front axle component degradation. The vehicle 2400 again has amid-engine mounting position for the ICE 2302.

FIG. 25 shows the rear wheel drive vehicle 2500 with a transmissionsystem 2502 where the ICE 2504 is mounted in the front of the vehicleand a drive shaft 2505 and/or other suitable mechanical componentsprovide rotational coupling between the ICE 2504 and the multi-speedgearbox 2506 that has an electric machine 2508. In this way, the enginemay be front mounted which may provide a desired weight distribution inthe vehicle for certain vehicle platforms.

FIG. 26 shows yet another vehicle 2600 that includes the steerable frontelectric axle assembly 2312 as well as an electric rear axle assembly2602 that includes a gearbox 2604 and an electric machine 2606.

FIGS. 1-27 provide for a vehicle product line that may include two ormore of the transmission systems described herein. For instance, thevehicle product line may include the transmission system 104, shown inFIG. 1 , as well as a first transmission system and any of thetransmission systems shown in FIGS. 11-19 and 27 , as a secondtransmission system. The two transmission systems included in theproduct line may share a common number of operating gears. In this way,these transmission systems may be more efficiently manufactured anddeveloped. The bearing layout and types of bearings of at least aportion of the bearings in the two transmission systems may also besimilar, which may allow further gains in manufacturing and developmentefficiency. In the two transmission systems in the product line, theclutch layout, particularly on the secondary shaft, may be similar, inone example, to further decrease manufacturing costs. Further in certainexamples, the two transmissions may have housing sections that have anequivalent size and shape to further simplify transmissionmanufacturing. As such, the housing sections in both transmissions mayenclose separate sets of gears.

FIGS. 20-22 are drawn approximately to scale, although other relativedimensions between the components may be used, in other embodiments.

FIGS. 1-2H and 2J-27 show example configurations with relativepositioning of the various components. If shown directly contacting eachother, or directly coupled, then such elements may be referred to asdirectly contacting or directly coupled, respectively, at least in oneexample. Similarly, elements shown contiguous or adjacent to one anothermay be contiguous or adjacent to each other, respectively, at least inone example. As an example, components laying in face-sharing contactwith each other may be referred to as in face-sharing contact. Asanother example, elements positioned apart from each other with only aspace there-between and no other components may be referred to as such,in at least one example. As yet another example, elements shownabove/below one another, at opposite sides to one another, or to theleft/right of one another may be referred to as such, relative to oneanother. Further, as shown in the figures, a topmost element or point ofelement may be referred to as a “top” of the component and a bottommostelement or point of the element may be referred to as a “bottom” of thecomponent, in at least one example. As used herein, top/bottom,upper/lower, above/below, may be relative to a vertical axis of thefigures and used to describe positioning of elements of the figuresrelative to one another. As such, elements shown above other elementsare positioned vertically above the other elements, in one example. Asyet another example, shapes of the elements depicted within the figuresmay be referred to as having those shapes (e.g., such as being circular,straight, planar, curved, rounded, chamfered, angled, or the like).Further, elements shown intersecting one another may be referred to asintersecting elements or intersecting one another, in at least oneexample. Further still, an element shown within another element or shownoutside of another element may be referred as such, in one example. Evenfurther, elements that are coaxial or offset from one another may bereferred to as such. Still further, a component that is fixedly coupledfor rotation with another component may be referred to as such.Components arranged parallel, coaxial, or perpendicular to one anothermay be referred to as such.

The invention will be further described in the following paragraphs. Inone aspect, a hybrid transmission system is provided that comprises: amulti-speed gearbox configured to rotationally couple a prime mover andan electric machine to different gear ratios during a hybrid drive mode,the multi-speed gearbox including: an electric drive interface gearpositioned coaxial to a first primary shaft and a second primary shaft;and an output shaft that includes an output shaft gear which is fixedlycoupled thereto meshes with a gear on a secondary shaft; wherein theelectric drive interface gear is axially positioned between two gearsthat are coaxial to the first primary shaft; wherein the electric driveinterface gear is idly mounted, free to spin, to the second primaryshaft; and wherein the electric drive interface gear is configured to beselectively connected to the second primary shaft and the secondaryshaft.

In another aspect, a hybrid transmission system is provided thatcomprises a multi-speed gearbox configured to rotationally couple aprime mover and an electric machine to different gear ratios during ahybrid drive mode, the multi-speed gearbox including: an electric driveinterface gear positioned coaxial to a first primary shaft and a secondprimary shaft; and an output shaft that includes an output shaft gearwhich is fixedly coupled thereto meshes with a gear on a secondaryshaft; wherein the electric drive interface gear is axially positionedbetween two gears that are coaxial to the first primary shaft; whereinthe electric drive interface gear is idly mounted, free to spin, to thesecond primary shaft; and wherein the electric drive interface gear isconfigured to be selectively connected to the second primary shaft andthe secondary shaft.

In any of the aspects or combinations of the aspects, the electric driveinterface gear and meshes with: a first secondary shaft gear that isidly mounted, free to spin, on a secondary shaft; and an electricmachine gear.

In any of the aspects or combinations of the aspects, the electric driveinterface gear meshes with: a first secondary shaft gear that is idlymounted, free to spin, on the secondary shaft; and an electric machinegear in an electric machine gear set.

In any of the aspects or combinations of the aspects, the gears in theelectric machine gear set may be radially aligned with the electricmachine interface gear.

In any of the aspects or combinations of the aspects, the gears in theelectric machine gear set and the electric machine interface gear may bealigned with regard to a longitudinal axis.

In any of the aspects or combinations of the aspects, the hybridtransmission system may further comprise a dual-clutch configured toselectively couple a prime mover to the first primary shaft and thesecond primary shaft and in the hybrid drive mode, the electric machinecontinuously provides mechanical power to the multi-speed gearbox whilethe dual-clutch shifts between two operating gears.

In any of the aspects or combinations of the aspects, the secondaryshaft may be positioned between the output shaft and the first primaryshaft.

In any of the aspects or combinations of the aspects, the hybridtransmission system may further include a clutch that selectivelycouples a gear which is idly mounted on the secondary shaft and mesheswith the traction motor interface gear with the secondary shaft.

In any of the aspects or combinations of the aspects, the multi-speedgearbox may include a traction motor gear set that includes a gear on atraction motor output shaft and wherein the traction motor gear set maybe radially aligned with the traction motor interface gear and whereinthe secondary shaft is positioned between the output shaft and the firstand second primary shafts.

In any of the aspects or combinations of the aspects, the multi-speedgearbox may further include a prime mover clutch configured toselectively couple a prime mover to the first primary shaft.

In any of the aspects or combinations of the aspects, the gear ratiodriven by the electric machine may be different than the gear ratiodriven by the prime mover.

In any of the aspects or combinations of the aspects, the prime moverclutch may be a dual-clutch and in the hybrid drive mode, the electricmachine may continuously provide mechanical power to the multi-speedgearbox while the dual-clutch shifts.

In any of the aspects or combinations of the aspects, the hybridtransmission system may further include an electric drive clutch that isconfigured to selectively couple the electric drive interface gear to asecond primary shaft.

In any of the aspects or combinations of the aspects, the electric driveclutch may be a synchronizer.

In any of the aspects or combinations of the aspects, the electric driveclutch and a gear clutch on the secondary shaft may be positioned inequivalent axial positions.

In any of the aspects or combinations of the aspects, the hybridtransmission system may further include a coupling device configured toselectively couple the first primary shaft and a second primary shaft.

In any of the aspects or combinations of the aspects, the hybridtransmission system may further include an electric front axle andwherein the multi-speed gearbox is included in a dual-clutchtransmission that is configured to operate in neutral.

In any of the aspects or combinations of the aspects, the hybridtransmission system may further comprise a dual-clutch that selectivelycouples the first and second primary shafts to the internal combustionengine.

In any of the aspects or combinations of the aspects, the traction motorinterface gear may be arranged coaxial to the first primary shaft andthe second primary shaft.

In any of the aspects or combinations of the aspects, the traction motorinterface gear may be idly mounted, free to spin, to the second primaryshaft.

In any of the aspects or combinations of the aspects, the hybridtransmission system may be included in a rear axle assembly.

In any of the aspects or combinations of the aspects, a rotational axisof the traction motor may be parallel to the first primary shaft and thesecond primary shaft.

In any of the aspects or combinations of the aspects, the transmissionmay further comprise an output shaft rotationally coupled to adifferential, wherein a rotational axis of the differential is arrangedperpendicular to a rotational axis of the electric machine.

In any of the aspects or combinations of the aspects, the hybridtransmission system may further comprise a synchronizer that isconfigured to selectively couple the electric drive interface gear to asecond primary shaft.

In any of the aspects or combinations of the aspects, the internalcombustion engine may be mounted in a front a vehicle.

In any of the aspects or combinations of the aspects, the hybridtransmission system may further comprise a park lock assembly coupled tothe output shaft.

Note that the example control and estimation routines included hereincan be used with various powertrain and/or vehicle systemconfigurations. The control methods and routines disclosed herein may bestored as executable instructions in non-transitory memory and may becarried out by the control system including the controller incombination with the various sensors, actuators, and other powertrainhardware. The specific routines described herein may represent one ormore of any number of processing strategies such as event-driven,interrupt-driven, multi-tasking, multi-threading, and the like. As such,various actions, operations, and/or functions illustrated may beperformed in the sequence illustrated, in parallel, or in some casesomitted. Likewise, the order of processing is not necessarily requiredto achieve the features and advantages of the example embodimentsdescribed herein, but is provided for ease of illustration anddescription. One or more of the illustrated actions, operations, and/orfunctions may be repeatedly performed depending on the particularstrategy being used. Further, the described actions, operations, and/orfunctions may graphically represent code to be programmed intonon-transitory memory of the computer readable storage medium in thepowertrain control system or transmission control system or vehiclecontrol system, that may use different communication channels toexchange data and messages to provide an higher level of integration andinteraction of prime mover, transmission, electric motor and inverter,where the described actions are carried out by executing theinstructions in a system including the various powertrain hardwarecomponents in combination with the electronic controller.

It will be appreciated that the configurations and routines disclosedherein are exemplary in nature, and that these specific embodiments arenot to be considered in a limiting sense, because numerous variationsare possible. For example, the above technology can be applied to hybridvehicles with various engine types such as V-4, V-6, I-4, I-6, V-8,V-10, V-12, V-16, W16, opposed 4, and other suitable types of engines.The transmission housing (e.g., front housing) may be bespoke fordifferent types of engines and also may be designed for front engineapplications to be coupled with a torque tube, for example.

As used herein, the terms “approximately” and “substantially” may beconstrued to mean plus or minus five percent of a value or range, unlessotherwise specified.

The following claims particularly point out certain combinations andsub-combinations regarded as novel and non-obvious. These claims mayrefer to “an” element or “a first” element or the equivalent thereof.Such claims should be understood to include incorporation of one or moresuch elements, neither requiring nor excluding two or more suchelements. Other combinations and sub-combinations of the disclosedfeatures, functions, elements, and/or properties may be claimed throughamendment of the present claims or through presentation of new claims inthis or a related application. Such claims, whether broader, narrower,equal, or different in scope to the original claims, also are regardedas included within the subject matter of the present disclosure.

1. A hybrid transmission system comprising: a multi-speed gearboxconfigured to rotationally couple a prime mover and an electric machineto different gear ratios during a hybrid drive mode, the multi-speedgearbox including: an electric drive interface gear positioned coaxialto a first primary shaft and a second primary shaft; and an output shaftthat includes an output shaft gear which is fixedly coupled theretomeshes with a gear on a secondary shaft; wherein the electric driveinterface gear is axially positioned between two gears that are coaxialto the first primary shaft; wherein the electric drive interface gear isidly mounted, free to spin, to the second primary shaft; and wherein theelectric drive interface gear is configured to be selectively connectedto the second primary shaft and/or the secondary shaft.
 2. The hybridtransmission system of claim 1, wherein the electric drive interfacegear meshes with: a first secondary shaft gear that is idly mounted,free to spin, on the secondary shaft; and an electric machine gear in anelectric machine gear set.
 3. The hybrid transmission system of claim 2,wherein the gears in the electric machine gear set and the electricmachine interface gear are aligned with regard to a longitudinal axis.4. The hybrid transmission system of claim 1, wherein a gear ratiodriven by the electric machine is different than a gear ratio driven bythe prime mover.
 5. The hybrid transmission system of claim 1, furthercomprising a dual-clutch configured to selectively couple a prime moverto the first primary shaft or the second primary shaft and in the hybriddrive mode, the electric machine continuously provides mechanical powerto the multi-speed gearbox while the dual-clutch shifts between twooperating gears.
 6. The hybrid transmission system of claim 1, furthercomprising an electric drive clutch that is configured to selectivelycouple the electric drive interface gear to the second primary shaft. 7.The hybrid transmission system of claim 6, wherein the electric driveclutch is a synchronizer.
 8. The hybrid transmission system of claim 1,wherein the secondary shaft is positioned between the output shaft andthe first primary shaft.
 9. The hybrid transmission system of claim 1,further comprising a coupling device configured to selectively couplethe first primary shaft and a second primary shaft.
 10. The hybridtransmission system of claim 1, further comprising a park lock assemblycoupled to the output shaft.
 11. A dual-clutch hybrid transmissionsystem, comprising: a multi-speed gearbox configured to rotationallycouple an internal combustion engine and traction motor to differentgear ratios during a hybrid drive mode, the multi-speed gearboxincluding: a traction motor interface gear positioned coaxial to a firstprimary shaft, a second primary shaft, and the internal combustionengine; an output shaft that includes an output shaft gear which isfixedly coupled thereto meshes with a gear on a secondary shaft; and adual-clutch that selectively couples the first and second primary shaftsto the internal combustion engine; wherein the traction motor interfacegear is axially positioned between two gears that are coaxial to thefirst primary shaft; wherein the traction motor interface gear is idlymounted, free to spin, to the second primary shaft; and wherein thetraction motor interface gear selectively connects to the second primaryshaft and/or the secondary shaft.
 12. The dual-clutch hybridtransmission system of claim 11, further comprising a clutch thatselectively couples a gear which is idly mounted on the secondary shaftand meshes with the traction motor interface gear with the secondaryshaft.
 13. The dual-clutch hybrid transmission system of claim 11,wherein the multi-speed gearbox includes a traction motor gear set thatincludes a gear on a traction motor output shaft and wherein thetraction motor gear set is radially aligned with the traction motorinterface gear and wherein the secondary shaft is positioned between theoutput shaft and the first and second primary shafts.
 14. Thedual-clutch hybrid transmission system of claim 13, wherein the tractionmotor interface gear is idly mounted, free to spin, to the secondprimary shaft.
 15. The dual-clutch hybrid transmission system of claim11, wherein the dual-clutch hybrid transmission system is included in arear axle assembly.
 16. The dual-clutch hybrid transmission system ofclaim 11, wherein a rotational axis of the traction motor is parallel tothe first primary shaft and the second primary shaft.
 17. Thedual-clutch hybrid transmission system of claim 11, further comprising adifferential, wherein a rotational axis of the differential is arrangedperpendicular to a rotational axis of the traction motor.
 18. Thedual-clutch hybrid transmission system of claim 11, further comprising asynchronizer that is configured to selectively couple the electric driveinterface gear to the second primary shaft.
 19. The dual-clutch hybridtransmission system of claim 11, wherein the internal combustion engineis mounted in a front a vehicle.
 20. The dual-clutch hybrid transmissionsystem of claim 11, further comprising a park lock assembly coupled toan output shaft.